Genetically engineered cells are provided which can serve as universal donor cells in such applications as reconstruction of vascular linings or the administration of therapeutic agents. The cells include a coding region which provides protection against complement-based lysis, i.e., hyperacute rejection. In addition, the cell's natural genome is changed so that functional proteins encoded by either the class II or both the class I and the class II major histocompatibility complex genes do not appear on the cell's surface. In this way, attack by T-cells is avoided. Optionally, the cells can include a self-destruction mechanism so that they can be removed from the host when no longer needed.